What’s grosser than gross? Slimy green mold growing in kids’ juice boxes. When the drinks are preservative-free, defects in the packaging can allow oxygen in and fungus to grow.

Moldy or fermented juice is not particularly dangerous to drink, said pediatrician Dr. Kathleen Berchelmann of St. Louis Children’s Hospital. One concerned parent recently took a Juicy Juice box filled with mold to the St. Louis hospital; the juice was not past its expiration date, and the child who drank it had no symptoms.

Berchelmann is taking the opportunity to advise parents against giving juice to kids because of its sugar content and low nutritional value. The American Academy of Pediatrics recommends kids eat whole fruits over fruit juice.

“For me as a pediatrician, this is an opportunity to catch people’s attention and talk about that kids really shouldn’t be drinking their calories,” Berchelmann said. “Juice is not a health food.”

The problem is not just with Juicy Juice, advertised as 100 percent fruit juice. An Indiana State biology student recently found five types of fungus in Capri Sun packaged drinks as part of a research project.

Leah Horn spent her senior year using a vacuum to filter the drinks and search for fungal microbes. She found three species of fungus in the tropical punch flavor and one each in the roaring waters and fruit punch flavors.

On its website, Kraft Foods answers questions about mold found in Capri Sun drinks, which are also free of preservatives. The company has added a disclaimer to its cartons about tossing any damaged or leaking pouches, while acknowledging that microscopic holes don’t cause leaks but allow for mold to grow.

The company states that the mold in Capri Sun is similar to that found on bread and cheese and other foods, adding: “And yes, it can be ugly, gross and totally unappealing. It would be great if foods stayed fresh forever. But the basic laws of science and nature dictate that most foods eventually spoil and get moldy.”

— St. Louis Post-Dispatch